(Reuters) - New Jersey's senate approved a bill on Thursday to prevent licensed therapists from counseling gay and lesbian youths to change their sexual orientation, a day after the Supreme Court handed the gay rights movement two significant victories.

The measure will now go to Republican Governor Chris Christie. Christie's office did not comment on whether he would sign or veto the bill, but gay rights advocates expressed optimism that New Jersey would become the second state after California to outlaw conversion therapy for people under the age of 18.

Citing medical and psychiatric research that sexual orientation is determined at birth, the bill would ban state-licensed counselors, therapists and social workers from practicing a method of talk therapy that opponents have said is deeply damaging to the self esteem and identity of gay youths.

The state Senate voted 28 to 9 to outlaw the therapy for minors. The bill was approved by New Jersey's lower house on Monday.

"I think Governor Christie will sign it," said Troy Stevenson, executive director of the gay rights group Garden State Equality. "He's given indication he will and he's fair-minded."

Stevenson said New Jersey's action "sends a message that this is wrong and that society won't accept it anymore."

Conversion therapy has become increasingly controversial, and last week the California-based Exodus International, a Christian group championing it, apologized for the harm it caused and said it was shutting its doors after 38 years.

The New Jersey measure could face a legal challenge.

"It absolutely violates parental rights," said John Tomicki of the League of American Families.

On Wednesday the Supreme Court struck down a provision of the 17-year-old Defense of Marriage Act that denied federal benefits to same-sex couples in states where they are legally married. The court also declined to rule on a case overturning a lower court decision striking down California's proposition 8, which banned gay marriage. The decision paves the way for same-sex marriage to resume in California.